I understand why you reported them but, hope you get no other problems from them from doing that. In our area there are over time parked vehicles as well as non registered ones. The police basically ignore them if they are not hurting anything. If you report them and they get into legal trouble they often "strike back" at who ever reported them. It is aggravating to see people who get by with ignoring any laws but unless it directly involves you at times it is better to ignore it unless it is a major offense. Often even tagged vehicles here are ignored and let stay where they are.